Electrosurgery is the application of radio frequency electrical energy to biological tissue to cut, coagulate, desiccate, or fulgurate tissue. Electrosurgical units typically include an electrosurgical generator configured to supply the electrical energy, and an electrosurgical hand piece configure to electrically couple with the electrosurgical unit and deliver the electrical energy to the tissue. To determine the desired electrical energy requested by the user of the hand piece, the electrosurgical unit may include one or more energized detection circuits that are configured to transmit energy requests from the electrosurgical hand piece to the electrosurgical generator, which is configured to supply electrosurgical energy to the electrosurgical hand piece. The energized detection circuit typically includes one or more detection circuits that electrically couple to one or more finger switches on the electrosurgical hand piece.
Presently, each finger switch on the electrosurgical hand piece includes an associated isolation transformer as part of the energized detection circuits. For example, an electrosurgical hand piece including three finger switches for three different power modes would typically include at least three isolation transformers in the energized detection circuit. However, radiofrequency leakage current, which is inadvertent electrical current between the electrosurgical unit and the ground, is related to the number of electrical components across the isolation barrier between the electrosurgical unit and the patient. Radiofrequency leakage current can harm the patient by causing patient burns, thus it is desirous to minimize leakage current. Because leakage current is related to parasitic capacitance across the transformers, the more transformers across the isolation barrier the more leakage current.